The patch titled
Subject: fs/filesystems.c: downgrade user-reachable WARN_ONCE() to pr_warn_once()
has been added to the -mm tree. Its filename is
fs-filesystemsc-downgrade-user-reachable-warn_once-to-pr_warn_once.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/fs-filesystemsc-downgrade-user-reachable-warn_once-to-pr_warn_once.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/fs-filesystemsc-downgrade-user-reachable-warn_once-to-pr_warn_once.patch
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------------------------------------------------------
From: Eric Biggers <ebiggers@xxxxxxxxxx>
Subject: fs/filesystems.c: downgrade user-reachable WARN_ONCE() to pr_warn_once()
After request_module(), nothing is stopping the module from being unloaded
until someone takes a reference to it via try_get_module().
The WARN_ONCE() in get_fs_type() is thus user-reachable, via userspace
running 'rmmod' concurrently.
Since WARN_ONCE() is for kernel bugs only, not for user-reachable
situations, downgrade this warning to pr_warn_once().
Link: http://lkml.kernel.org/r/20200312202552.241885-3-ebiggers@xxxxxxxxxx
Signed-off-by: Eric Biggers <ebiggers@xxxxxxxxxx>
Cc: Alexei Starovoitov <ast@xxxxxxxxxx>
Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Cc: Jeff Vander Stoep <jeffv@xxxxxxxxxx>
Cc: Jessica Yu <jeyu@xxxxxxxxxx>
Cc: Kees Cook <keescook@xxxxxxxxxxxx>
Cc: Luis Chamberlain <mcgrof@xxxxxxxxxx>
Cc: NeilBrown <neilb@xxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/filesystems.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
--- a/fs/filesystems.c~fs-filesystemsc-downgrade-user-reachable-warn_once-to-pr_warn_once
+++ a/fs/filesystems.c
@@ -272,7 +272,9 @@ struct file_system_type *get_fs_type(con
fs = __get_fs_type(name, len);
if (!fs && (request_module("fs-%.*s", len, name) == 0)) {
fs = __get_fs_type(name, len);
- WARN_ONCE(!fs, "request_module fs-%.*s succeeded, but still no fs?\n", len, name);
+ if (!fs)
+ pr_warn_once("request_module fs-%.*s succeeded, but still no fs?\n",
+ len, name);
}
if (dot && fs && !(fs->fs_flags & FS_HAS_SUBTYPE)) {
_
Patches currently in -mm which might be from ebiggers@xxxxxxxxxx are
kmod-make-request_module-return-an-error-when-autoloading-is-disabled.patch
fs-filesystemsc-downgrade-user-reachable-warn_once-to-pr_warn_once.patch
docs-admin-guide-document-the-kernelmodprobe-sysctl.patch
selftests-kmod-test-disabling-module-autoloading.patch
